U.S. Pat. No. 4,097,763, which is assigned to the present assignee, describes and claims an electric controller which is intended to accomplish the same general purpose as the solid state controller of the present invention. The controller of the present invention, however, constitutes a distinct improvement over the controller described in the patent, in that the mechanical elements of the prior controller have been replaced by solid state electronic components, and additional control functions have been incorporated therein. The controller of the invention is also advantageous in that it is relatively simple to program and operate, and it is capable of extended trouble-free operation.
The controller of the invention is capable of turning a plurality of sprinkler valves on and off automatically in sequence; and it permits the user to water each of a number of watering zones on a separate schedule, using any combination of weekdays and time intervals during each day. The controller is also capable of automatically turning a water pump or master valve on and off. A self-prompting liquid crystal display makes it easy to set up any desired watering schedule, and to review the established watering schedules from time-to-time. The display serves to guide the user through each step required to program the unit by appropriate words and numbers.
The controller to be described is constructed to permit the user to water, for example, up to four times a day, if so desired, which is ideal for new lawns. It also permits the user to water up to thirteen hours a day which is ideal for drip irrigation. A pause control makes it easy to interrupt the watering cycles for yard activities. Also, a manual operating mode permits the user to water manually when an automatic watering cycle is not in progress.
The controller to be described also includes an electronic circuit which removes a malfunctioning valve from the system, but which enables the system to continue normal control of the other valves, thereby preventing shut-down of the system. The circuit also incorporates a diagnostic feature which causes the malfunctioning valve number to appear on the liquid crystal display for easy repair.
The controller of the invention is of the same general type as the solid state controller described in Kendall et al U.S. Pat. No. 4,165,532. However, the controller of the invention incorporates certain features and improvements do not appear in the Kendall apparatus.